1. Field of the Invention
The invention relates to a turret indexing system and more particularly to a stamping tool that positions tools for striking by a ram.
2. Description of the Prior Art
Turret type punch presses which are capable of accurately positioning different tools in a single system are well-known. Conventional presses are controlled by a central processor such as a computer. Such a press is disclosed in U.S. Pat. No. 4,285,259. Conventional punch presses have tool holders which are rotatably mounted in the turrets. The punching tools can be automatically and synchronously rotated or indexed in the upper and lower turrets to provide different orientations for the punching of holes by the tools. Such a turret indexing system is disclosed in U.S. Pat. No. 4,412,469. To improve performance, these presses include a means for simultaneous adjustment of the cutting height and stroke of each tool. The adjustment will be made according to the needs of the particular job. Such an adjustment system is disclosed in U.S. Pat. No. 3,174,377.
U.S. Pat. No 4,658,688, assigned to the assignee of the present application, discloses a punch press having multiple punch tool rotatable turrets wherein at least one of the punch tools on each of upper and lower turrets is indexable to different angular orientations. Rotation of the indexable punch tools is accomplished by a slidably mounted motor for engagement with a timing pulley, which through a timing belt and speed reducing element, acts to rotate the punch tools. A break and position sensors are also provided Synchronization of punch and die orientation is achieved through servos and control.
U.S. Pat. No. 4,569,267 discloses a punch press which uses a punch tool assembly which contains at least two punch pins of different diameters or cross-sections which are interchangeable in the working position by a control element which is slidable about the pin support member, and actuating means. When the punch tool assembly is rotatable about the ram to effect the movement of the punch pins from operative to inoperative positions, then a cooperating movable die is provided in order to ensure that the aligned die bores are cooperatively dimensioned and configured with respect to the punch pins. The punch tool assembly is held on the ram and moves with the ram and the pins, when not being used, are held in an elevated position while the operative pin is rigidly locked into a protruding position.
Prior art punch presses also utilize an overload protection system to prevent any damage. The press will be able to exert its thrust on the work up to a predetermined pressure, yielding to the overload release device to prevent damage. Such a device is disclosed in U.S. Pat. No. 2,438,851.
Most turret type presses are directed toward punching but can be adapted to stamping. Such a tool is produced by Finn Manufacturing. This tool requires movement of the striker area over the stationary character inserts to prepare them for striking by a ram. The means provided, for tool length adjustment and overload protection in the prior art is not appropriate for stamping because they lack the accuracy needed for optimum performance. Stamping requires precise adjustment to insure consistent depth of impression by the tool. Accordingly, a stamping tool with a turret indexing system having automatic adjustment of tool length and mechanism for overload protection when the tool length is not adjusted correctly, will be a decided advance in the state of the art.